Michael is 5 times as old as Ben and is also 40 years older than Ben. How old is Michael?
Explanation: We can use the given information to write down two equations that describe the ages of Michael and Ben. Let Michael's current age be $m$ and Ben's current age be $b$ $m = 5b$ $m = b + 40$ Now we have two independent equations, and we can solve for our two unknowns. One way to solve for $m$ is to solve the second equation for $b$ and substitute that value into the first equation. Solving our second equation for $b$ , we get: $b = m - 40$ . Substituting this into our first equation, we get the equation: $m = 5$ $(m - 40)$ which combines the information about $m$ from both of our original equations. Simplifying the right side of this equation, we get: $m = 5m - 200$ Solving for $m$ , we get: $4 m = 200$ $m = 50$.